Many systems are presently known for the capture and display of video information.
At least one of these systems provides for a picture within a picture display. The system is designed to overlay a small picture on the normal frame. The system starts with a digital signal and to create the small picture subsamples one out of five averaged horizontal samples and one out of three averaged lines vertically. The chrominance portion is further averaged over every four subsamples, or pixels, in a line while the luminance for each pixel is retained. However, the picture is distorted from one line to the next by averaging chrominance across one portion of one line without taking into account the chrominance on the next line. This distortion is acceptable in a picture in a picture system where the second picture is meant to be displayed at a reduced size. The chrominance averaging across a line was used as it is simple to implement through time division multiplexing of the reduced video signal.
Another system for the capture and display of video information first separates the chrominance and luminance by ordinary analog separation before they are digitized. It has been shown that this method of separation results in impairment to the picture quality. Digitizing the video signal prior to separation provides a much better separation of the luminance and chrominance components. This method greatly reduces distortion caused by the incomplete separation that is typical of analog separation methods. The same system also averages information over every four pixels in a line creating the distortion discussed above.
Numerous display systems for displaying digitized and separated luminance and chrominance that have been stored in a memory are known. Some systems store the chrominance data in a separate memory.
Also known are systems that digitize the video information and store the data in a frame memory. This allows the video to be separated digitally. These systems however use various circuits to implement the separation instead of using a computer that can employ more complicated manipulations to handle noise and motion effects.
None of the systems allow for the efficient use of data with averaging of chrominance over an area, nor do they allow for the accessing of captured and stored information by an external computer for separation into component parts and averaging or for graphical manipulation of the information.